Yes, they are the same size and as noted in the table Frank provided, the 377272 rods can be used on the 30 and 35hp OMC motors from 1956 thru the late 1950’s including your ’57 Javelin. I just swapped a set of the ’58 rods into my ’56 30hp. See pic for comparison – note different wrist pin bearings.
Edit – wrong 1958 part number posted in pic – should be 377272.
Bob
1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1957 Evinrude 3022
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20
1982 Evinrude 25hp
“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."
